LEASES - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Operating lease cost:
Lease cost	$ 11.4	$ 21.8
Variable lease cost	2.8	5.7
Total operating lease cost	14.2	27.5
Short-term lease cost	1.1	2.2
Finance lease cost:
Amortization of right-of-use assets	0.7	1.5
Interest on lease liabilities	0.0	0.1
Total finance lease cost	0.7	1.6
Total lease cost	$ 16.0	$ 31.3